Cauldra, it is similar in NY where you can own and carry a switchblade or gravity knife for use while fishing, trapping and hunting, but it is illegal to sell or transfer them in any way. I suspect that the PA law is similar to the NY law in that these exceptions that allow ownership were written in to cover persons owning the knives at the time of the ban. If the switchblade tooth fair leaves them under your pillow then you are OK....lol